1. Field of the Invention
The present invention generally relates to multi-service communications systems wherein a plurality of different services are transmitted to subscriber locations over one or more different frequency channels. More particularly, the present invention relates to an apparatus for providing dynamic virtual service selection in such multi-service communications systems. A dynamic virtual service comprises a group of related services wherein different ones of the group are active on a time-varying basis.
2. Description of the Prior Art
Communications systems today have the ability to simultaneously transmit a multitude of video, audio, teletext and data services to subscribers. For example, with the advent of digital compression technologies, the subscription television industry has experienced an explosion in the number of services that can be provided to each subscriber.
Consequently, subscribers face an overwhelming choice of available services and providing efficient and inventive ways for subscribers to access these services is extremely important.
Most multi-service communications systems transmit different services over one or more different frequency channels. Each frequency channel may carry more than one service. Accessing a particular service requires tuning to the frequency channel carrying that service, and then selecting that service from the many services carried on that frequency channel. Generally, it is desirable to insulate subscribers from the details of service access and to allow subscribers to access different services in a like manner. Subscription television operators typically assign each service a unique number and then provide subscribers with a decoder that allows the subscriber to access a particular service by selecting that service's number using a push-button device or hand-held remote. Subscribers are thereby insulated from the complex details of service acquisition.
It is further desirable to provide system operators with the ability to easily re-assign service numbers to different services. Some services may be discontinued and others may be added, and therefore, a static numbering system rapidly becomes obsolete. Bennett et al., U.S. Pat. No. 4,908,859, describe an interface system for use at subscriber locations which provides system operators with some degree of flexibility. Bennett et. al. employ a mapping scheme that maps each of the services received on various frequency channels to a different subscriber selectable "interface channel." Essentially, Bennett et. al. provide a one-to-one mapping of each service to a particular subscriber selectable "interface channel." System operators can re-assign a service to a different interface channel as needed, such as when services are added or deleted from the system. Although the system of Bennett et. al. provides some degree of flexibility in defining access to various services, more flexible and creative means for providing subscriber access are needed as compression technologies make it possible to provide an ever increasing number of available services. The present invention satisfies this need.